B=-5x(10-2x)

Solution for B=-5x(10-2x) equation:

=-5B(10-2B)

We move all terms to the left:

-(-5B(10-2B))=0

We add all the numbers together, and all the variables

-(-5B(-2B+10))=0


We calculate terms in parentheses: -(-5B(-2B+10)), so:

-5B(-2B+10)

We multiply parentheses

10B^2-50B

Back to the equation:

-(10B^2-50B)


We get rid of parentheses

-10B^2+50B=0

a = -10; b = 50; c = 0;
Δ = b2-4ac
Δ = 502-4·(-10)·0
Δ = 2500
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$B_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$B_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{2500}=50$
$B_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(50)-50}{2*-10}=\frac{-100}{-20}
=+5
$
$B_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(50)+50}{2*-10}=\frac{0}{-20}
=0
$